Port Python SDK route generation from nextlove to Metalsmith (#581)

* feat: Replace nextlove sdk generator with metalsmith codegen

Replace the @seamapi/nextlove-sdk-generator based route generation with
the metalsmith + handlebars + @seamapi/blueprint architecture used by
seamapi/javascript-http. The generated output under seam/routes/ is
byte-identical.

The blueprint drives the route, endpoint, and namespace structure. The
raw OpenAPI spec is still consulted wherever the nextlove generator
derived output from data the blueprint normalizes differently (integer
vs number types, resource schema set and order, parameter flattening);
each of those spots carries a TODO to migrate to the blueprint once
output is allowed to change.

- Add codegen/ with the Metalsmith pipeline, plugin, context builders,
  and Handlebars layouts and partials
- Remove generate-routes.js
- Pin @seamapi/types at 1.910.0 for output parity and use
  @seamapi/blueprint 0.55.0
- Bump del to ^8 to satisfy the @seamapi/smith peer range
- Ignore *.hbs and CODEGEN.md in a new .prettierignore since the
  glimmer parser mangles Python-flavored templates
- Re-include codegen/lib/ in .gitignore (the Python template ignores
  lib/) and ignore the generated CODEGEN.md seed

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019iX1vWXfXKzUyRJTVm8D7s

* docs: Mark all deferred codegen workarounds with TODO

Every comment describing behavior to address later now leads with TODO
so the deferred work is greppable: the parameter comparator precedence
quirk and the unwired deeply nested namespaces.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019iX1vWXfXKzUyRJTVm8D7s

* refactor: Simplify codegen setup to match seamapi/docs conventions

- Trim devDependencies to direct imports only: metalsmith,
  @metalsmith/layouts, jstransformer-handlebars, del, tsx, typescript,
  eslint, jiti, and mkdirp are @seamapi/smith peers that npm installs
  automatically, matching how seamapi/docs consumes smith
- Add tsconfig.json extending @seamapi/smith/tsconfig.base.json with a
  typecheck script and codegen/index.ts stub, mirroring seamapi/docs
  and seamapi/javascript-http
- Widen response type properties for exactOptionalPropertyTypes

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019iX1vWXfXKzUyRJTVm8D7s

* refactor: Align codegen scripts and imports with seamapi/docs

- Add lint, postlint, and preformat scripts using
  @seamapi/smith/eslint-config via a one-line eslint.config.ts,
  matching seamapi/docs
- Replace relative parent imports with lib/* path imports (tsconfig
  baseUrl and paths), satisfying import/no-relative-parent-imports and
  matching the smith import sort convention
- Mark every file and function that exists only for output parity with
  a TEMPORARY banner and a TODO to delete it once generated output is
  allowed to change, so temp code is skippable in review

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019iX1vWXfXKzUyRJTVm8D7s

* refactor: Drop tsconfig paths in favor of relative imports

Match how seamapi/docs consumes @seamapi/smith: extend the base
tsconfig with no compiler option overrides and use plain relative
imports in codegen.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019iX1vWXfXKzUyRJTVm8D7s

* fix: Move codegen gitignore rules to conventional positions

CODEGEN.md moves to the top of the file. The codegen/lib/ negation
moves next to the lib/ pattern it negates, since a gitignore negation
only takes effect after the pattern it overrides.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019iX1vWXfXKzUyRJTVm8D7s

* fix: Track the codegen content seed

The CODEGEN.md gitignore rule matches any depth, so the Metalsmith
source seed codegen/content/CODEGEN.md was never committed and CI
failed to generate with ENOENT on the missing directory. Force-add the
seed exactly as seamapi/javascript-http does; the ignore rule still
covers the generated CODEGEN.md at the repository root.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019iX1vWXfXKzUyRJTVm8D7s

* fix: Remove gitignore comment per review

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019iX1vWXfXKzUyRJTVm8D7s

* Update .gitignore to include codegen/lib exception

Add exception for codegen/lib in .gitignore

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: razor-x

.gitignore

@@ -5,6 +5,9 @@
 # For more details, visit the project page:
 # https://github.com/github/gitignore
 
+# Codegen
+CODEGEN.md
+
 # Temporary development files
 tmp
 
@@ -325,3 +328,6 @@ dist
 # yalc
 .yalc/
 yalc.lock
+
+# Codegen exceptions
+!codegen/lib/

.prettierignore

@@ -0,0 +1,4 @@
+# Prettier exceptions
+
+*.hbs
+CODEGEN.md

codegen/content/CODEGEN.md

@@ -0,0 +1 @@
+# Codegen

codegen/index.ts

@@ -0,0 +1 @@
+export default null

codegen/layouts/default.hbs

@@ -0,0 +1 @@
+{{contents}}

codegen/layouts/models.hbs

@@ -0,0 +1,17 @@
+from typing import Any, Dict, List, Optional, Union
+from typing_extensions import Self
+import abc
+from dataclasses import dataclass
+from ..utils.deep_attr_dict import DeepAttrDict
+
+{{#each resources}}
+
+{{> model-dataclass}}
+{{/each}}
+{{#each abstractClasses}}
+
+{{> abstract-route-class}}
+{{/each}}
+
+
+{{> abstract-routes}}

codegen/layouts/partials/abstract-route-class.hbs

@@ -0,0 +1,17 @@
+class {{className}}(abc.ABC):
+{{#if showPass}}
+    pass
+{{/if}}
+{{#each childProperties}}
+
+    @property
+    @abc.abstractmethod
+    def {{namespace}}(self) -> {{abstractClassName}}:
+        raise NotImplementedError()
+{{/each}}
+{{#each methods}}
+
+    @abc.abstractmethod
+    def {{name}}(self,{{#if hasParams}} *,{{/if}} {{signatureParams}}) -> {{returnType}}:
+        raise NotImplementedError()
+{{/each}}

codegen/layouts/partials/abstract-routes.hbs

@@ -0,0 +1,5 @@
+@dataclass
+class AbstractRoutes(abc.ABC):
+{{#each routesNamespaces}}
+    {{namespace}}: {{abstractClassName}}
+{{/each}}

codegen/layouts/partials/model-dataclass.hbs

@@ -0,0 +1,13 @@
+@dataclass
+class {{className}}:
+{{#each properties}}
+    {{name}}: {{type}}
+{{/each}}
+
+    @staticmethod
+    def from_dict(d: Dict[str, Any]):
+        return {{className}}(
+{{#each properties}}
+            {{name}}={{#if isDictParam}}DeepAttrDict({{/if}}d.get("{{name}}", None){{#if isDictParam}}){{/if}},
+{{/each}}
+        )

codegen/layouts/partials/route-method.hbs

@@ -0,0 +1,32 @@
+    def {{name}}(self,{{#if hasParams}} *,{{/if}} {{signatureParams}}) -> {{returnType}}:
+        json_payload = {}
+
+{{#each params}}
+        if {{name}} is not None:
+            json_payload["{{name}}"] = {{name}}
+{{/each}}
+
+        {{#unless returnsNone}}res = {{/unless}}self.client.post("{{path}}", json=json_payload)
+{{#if pollsActionAttempt}}
+
+        wait_for_action_attempt = (
+            self.defaults.get("wait_for_action_attempt")
+            if wait_for_action_attempt is None
+            else wait_for_action_attempt
+        )
+
+        return resolve_action_attempt(
+            client=self.client,
+            action_attempt=ActionAttempt.from_dict(res["action_attempt"]),
+            wait_for_action_attempt=wait_for_action_attempt
+        )
+{{else if returnsNone}}
+
+        return None
+{{else if isList}}
+
+        return [{{itemType}}.from_dict(item) for item in {{resAccessor}}]
+{{else}}
+
+        return {{returnType}}.from_dict({{resAccessor}})
+{{/if}}